The present disclosure relates to, in one embodiment, to TFTs for use in electronic devices having a display, e.g., TVs, mobile phones, etc., using LED and OLED technology. For such a display, at high resolution, smaller size and more stable transistors with lower power and lower mura defects are required.
Metal oxide semiconductors have been used for such device fabrication due to their high carrier mobility than amorphous Silicon, low processing temperatures, and optical transparency. However, thin film transistors (TFTs) made from metal oxide semiconductors are sensitive to hydrogen content, where hydrogen between layers can act as an amphoteric impurity, e.g., acts as a donor or acceptor, and can induce a high threshold voltage shift under voltage/light bias conditions.
Therefore, the present disclosure resulted from the recognition that there is a need for a TFT and manufacturing process that is less susceptible to the hydrogen impurity problems of the prior art.